1. Field of the Invention
The present invention relates to image processing systems, image data transmission apparatus, image data reception apparatus, and image processing methods. The present invention relates more particularly to an image processing system for applying a special effect generation process to given source pictures, an image data transmission apparatus for transmitting image data after applying a special effect generation process to given source pictures, an image data reception apparatus for receiving image data which has been manipulated by a special effect generation process, and an image processing method for applying a special effect generation process to given source pictures.
2. Description of the Related Art
MPEG (Moving Pictures Experts Group) standard coding techniques, a key technology in the multimedia age, are designed to process video images and associated audio and data in an integrated way, covering a wide range of applications including the use in local area networks (LAN) and broadcasting services. In recent years, the widespread proliferation of multimedia contents, as well as the increasing use of digital video compression techniques including MPEG, has enabled the consumers to enjoy a variety of video programs supplied from service providers in convenient and economical ways. Video on demand (VOD), for example, is a technology that makes this possible.
While such systems have enough capabilities to supply the users with high quality visual information of any kind on their requests, there are potential risks of violating legal rules and social guidelines in this shared audio and video environment. More specifically, immature users have to be protected from exposure to some classes of visual materials deemed inappropriate. Copyrighted pictures should not be circulated without permission of the copyright holder. Because of the increasing awareness of such potential problems, the providers control their own service contents by embedding some protection data into source pictures or using other special effect techniques to manipulate the source data.
Japanese Patent Application Laid-open Publication No. 6-54325 (1994), for instance, proposes a technique to reproduce images at remote sites. In this proposed system, the sender encrypts image data after applying orthogonal transform, and the receiving terminals reproduce the images with different quality levels determined in accordance with the decryption functions furnished therein.
It should be noted that the above proposed technique relies on a data encryption process to control the quality of reproduced pictures. This actually requires the sender to incorporate additional special circuitry for encryption, besides causing an increase in the volume of coded data.
Taking the above into consideration, a first object of the present invention is to provide an image processing system which can apply a special effect generation process with a simple circuit in an efficient way.
A second object of the present invention is to provide an image data transmission apparatus which transmits image data after applying a special effect generation process to given source pictures, with a simple circuit in an efficient way.
A third object of the present invention is to provide an image data reception apparatus which receives image data which has been manipulated by a special effect generation process, with a simple circuit in an efficient way.
A fourth object of the present invention is to provide an image processing method for efficiently applying a special effect generation process to given source pictures with a simple circuit configuration.
To accomplish the first object, there is provided an image processing system for applying a special effect generation process to a given source picture. This system comprises (a) an image data transmission apparatus and (b) an image data reception apparatus.
The image data transmission apparatus comprises: (a1) a target area specifying unit for specifying a target area of the given source picture that is to be subjected to the special effect generation process; (a2) an image data coding unit for generating coded data by encoding the source picture, (a3) a target data relocation unit for extracting target data from the coded data generated by the coded data generating unit and relocating the target data from an original field thereof to a different field of the coded data to obtain a coded bitstream for transmission, the target data being part of the coded data that is corresponding to the target area specified by the target area specifying unit, and (a4) an image data transmission unit for transmitting the coded bitstream obtained by the target data relocating unit.
The image data reception apparatus receives the coded bitstream from the image data transmission apparatus, which comprises: (b1) a target data extraction unit for extracting the target data from the received coded bitstream; (b2) a target data storage unit for storing the target data extracted by the target data extraction unit; (b3) a data reproduction unit for reproducing original coded data from the received coded bitstream by restoring the target data into the original field thereof, or reproducing imperfect coded data from the received coded bitstream without restoring the extracted target data; and (b4) a data decoding unit for decoding the original coded data or the imperfect coded data supplied from the data reproduction unit.
Further, to accomplish the second object, there is provided an image data transmission apparatus for transmitting image data after applying a special effect generation process to a given source picture. This apparatus comprises: (a) a target area specifying unit for specifying a target area of the given source picture that is to be subjected to the special effect generation process; (b) an image data coding unit for generating coded data by encoding the source picture; (c) a target data relocation unit for extracting target data from the coded data generated by the coded data generating unit and relocating the target data from an original field thereof to a different field of the coded data to obtain a coded bitstream for transmission, the target data being part of the coded data that is corresponding to the target area specified by the target area specifying unit; and (d) an image data transmission unit for transmitting the coded bitstream obtained by the target data relocating unit.
Moreover, to accomplish the third object, there is provided an image data reception apparatus for receiving image data that has been manipulated with a special effect generation process. This image data reception apparatus comprises: (a) a target data extraction unit for extracting target data from the received image data, the target data being part of the image data that has been subjected to the special effect generation process; (b) a target data storage unit for storing the target data extracted by the target data extraction unit; (c) a data reproduction unit for reproducing original coded data from the received image data by restoring the target data into an original field thereof, or reproducing imperfect coded data from the received image data without restoring the target data; and (d) a data decoding unit for decoding the original coded data or the imperfect coded data supplied from the data reproduction unit.
Furthermore, to accomplish the fourth object, there is provided an image processing method for applying a special effect generation process to a source picture. This method comprises the steps of: (a) specifying a target area of the given source picture as a subject of the special effect generation process; (b) compressing the given source picture by using discrete cosine transform coding techniques to produce coded data; (c) extracting target data out of the coded data, which corresponds to the target area, and relocating the target data to a different field of the coded data to obtain a coded bitstream for transmission, wherein the target data is part of the coded data that is corresponding to the target area; (d) transmitting the coded bitstream; (e) extracting the target data from the coded bitstream; (f) saving the extracted target data into storage; (g) reproducing original coded data from the coded bitstream by restoring the target data into an original location thereof, or reproducing imperfect coded data from the coded bitstream without restoring the extracted target data; and (h) decoding the coded data or the imperfect coded data.
The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example.